In 1983, President Reagan in the US declared ketchup was a vegetable, more recently, lobbyists representing pizza and cheese manufacturers obtained congressional concessions that 1/8 of a cup of tomato paste on the base of a pizza was the nutritional equivalent of 1/8 of a cup of vegetables.

In November 2011, Congress declared “Pizza is now a vegetable” (see Robert H. Lustig, “Fat Chance”).

This is an example of where we are currently at in respect of the types of food we eat today. Of course, tomatoes are actually fruit and besides tomatoes, often the paste on a pizza base like ketchup is also loaded full of with sugar and salt.

Most brands will go a step further and pump it with other nasties such as high fructose corn syrup. In both the US and the UK, there have been several attempts to address junk food and its impact on conditions such as childhood obesity and Type II diabetes. The First Lady’s “Let’s move”, program comes to mind which encourages children to move more, eat less, reduce portion sizes and cut back on snacks, but what is strikingly apparent is that there is absolutely no mention of the brain. Nutrition is addressed from the neck down and the focus is predominantly on the impact of diet on the body. There seems to be little attention to investigate and educate people about the effects of junk food to the function of the brain and its influence on learning, behavior, well-being and mood. This is despite increasing evidence linking poor diet and low omega-3 HUFA status with behavioral problems and diagnostic labels such as Attention Deficit Hyperactivity Disorder (ADHD).

There is no doubt that modern, ‘junk food’ diets are seriously damaging our physical health leading to increased rates of:

Obesity

Type-II Diabetes

Heart Disease & Stroke

Cancer

Allergies and auto-immune disorders

But, diet also affects our brain and behaviour.

There has been a huge dietary shift, especially in developed countries, including the US and UK and the quality of our foods and the nutritional composition of our diet has changed dramatically. This is argued to be a direct consequence of the Agricultural Revolution (17th Century to the end of the 19th Century and then continuing post World War II) in favor of mass food production, profit and shelf life resulting in the “Modern Western Diet” consumed by millions of people today.

Of course, technological advances have also led to a huge decline in the amount of physical exercise we take compared to our ancestors. In evolutionary terms, these diet and life-style changes have occurred too rapidly for our genetic, biochemical and physiological systems to be able to adapt to them.

Hugh Macdonald Sinclair was a doctor, medical researcher and expert in human nutrition who spent much of his academic life at Magdalen College, Oxford (4th Feb 1910 – 22 June 1990). Hugh along with Jorn Dyerberg spent time living and researching the diet of the Greenland Inuit population and noticed that coronary heart disease, cancer, diabetes, inflammation, strokes, skin disease as well as – allergies and auto-immune disorders were almost non-existent. The researchers also noticed that their diet mainly consisted of seal blubber, fish/seafood and water and calculated they were consuming in the region of 7 grams of omega-3 highly unsaturated fatty acids per day!

Shortly after his return, Sinclair wrote a landmark letter to the Lancet (1956), outlining his theories and proposing that Western diseases were the result of nutritional (EFA) deficiency. However, his theories were not well received. The idea that a fat could be useful was extremely controversial and in 1958, his Readership at Oxford abruptly ended. However, it has since become very clear that in any country adopting a Western-type diet that increased rates of a wide range of degenerative physical health disorders invariably follow hence the nickname “Disease of Civilization”. His theories have since sparked global research efforts and led to a much better understanding of the role of omega-3 fats in human disease. In fact, there is now an entire laboratory in his name at the University of Reading in Surrey, England: “Hugh Sinclair Unit of Human Nutrition”.

Western diseases were considered quite rare as recently as the 19th Century but now typically affect 60% of the population. It is important to consider that these diseases have “multi-factorial elements” and do not arise from just 1 or 2 aspects of our diets. For example, they do not exist because of diets containing excess saturated fats, or too much salt or a lack of a specific nutrient. Instead, a large number of diverse elements of our nutrition interact with our genetic inheritance along with a host of environmental factors over time, to create these “systemic” diseases.

There is no doubt that the industrialization of our food supply has led to higher intakes of saturated and hydrogenated vegetable oils and lower intakes of mono- and polyunsaturated fats. This has resulted in a change in the brain composition of omega-3 and 6 with current ratio estimates of 20:1 omega-6/omega-3. This imbalance in brain composition of essential dietary fats is theorized to have contributed negatively to both physical and mental ill-health. The changes in the American food supply in the 20th century were published by Blasbalg et al., (2011) an NIH research group demonstrating that the consumption of soybean oil has increased 1163 fold from 1909-1999. This finding demonstrates the over-representation of omega-6 Linolenic Acid (LA) in our diet.

Currently, there are an abundance of scientific findings linking the Western diet with alternations in the structure and function of the brain. Just recently, researchers using data from the Personality and Total Health Through Life Study examined a subsample of the cohort (n = 255) aged 60–64 years at baseline in 2001, who had completed a food frequency questionnaire, and also underwent two MRI scans approximately 4 years apart. They were interested whether there were any association between dietary patterns and hippocampal volume in humans, and to assess whether diet was associated with differential rates of hippocampal atrophy over time. They found that lower intakes of nutrient-dense foods and higher intakes of unhealthy foods were each independently associated with smaller left hippocampal volume. This is the first human study to demonstrate associations between diet and hippocampal volume supporting previous published research in animal models.

Dr. Hee-Yong Kim at the National Institutes of Health in Bethesda, Maryland (see Cao et al., & Kim HY., J. Neurochem. 2009) has publishing pioneering evidence demonstrating that gestational DHA-deprivation in fetal hippocampi significantly inhibited neurite outgrowth and synaptogenesis in cultured hippocampal neurons. Subsequent supplementation of DHA to the DHA-depleted neurons in culture, restored the neurite growth and synaptogenesis inhibited by embryonic DHA-deprivation in vivo, further supporting the unique role of DHA in promoting hippocampal development (see picture). The hippocampus is a seahorse shaped structure in the brain which is associated with both learning and memory, as well as mood regulation, and is specifically implicated in depression. It is also one of only two areas of the brain where adult neurogenesis is prevalent. Hippocampal neurogenesis is mediated by neurotrophins such as Brain Derived Neurotrophic Factor (BDNF) which is actually reduced by high fat/refined sugar diets.

Other studies including the Raine Study which was a longitudinal study conducted in Australia followed 2868 live births to age 14 years and then assessed the adolescents for dietary patterns and ADHD diagnosis. Data were available for 1799 adolescents, including 115 with a diagnosis of ADHD. The 2 main dietary patterns were assessed and categorized as “Healthy” and “Western.” The results showed that an increased likelihood of an ADHD diagnosis was significantly associated with the Western dietary pattern, after adjustment for potential confounding variables from pregnancy to adolescence. The ADHD diagnosis was not associated with the Healthy dietary pattern. The Western dietary pattern was correlated with higher intakes of total and saturated fat, salt, and refined sugars, and was inversely correlated with intake of folate, fiber, and omega-3 fatty acids.100 By contrast, the Healthy dietary pattern was positively correlated with fiber, folate, and omega-3 fatty acid intake, and inversely correlated with the amount of refined sugars and the total fat/saturated fat ratio.

Another research group from the University of Finland, Kuopio University hospital and Kuopio Research Institute of exercise and medicine tested 428 children aged 6-8 on a series of cognitive tests and found that boys with the lowest consumption of fruit and high-fibre grain products had the lowest scores. Of course, there are countless more examples and although correlation does not imply causation around 1/3 of all cancers are now thought to be attributable to dietary factors, and poor nutrition is also a major contributor to heart disease and stroke (see Cordain et al., 2005).

In 1976, the Royal College of Physicians and the British Cardiac Society recommended eating less fatty red meat and more poultry instead because it was lean. However, the situation has dramatically changed since that time, with a striking increase in fat content of the standard supermarket chicken. Dr. Wang and colleagues (2010) analyzed the fat extracted from intensively reared, supermarket chickens in England. They found that 1.3kg roasting chicken yielded 275g fat, and 600g lean meat – of which ¾ is water, so only 150g is protein.

The omega-6/omega-3 ratio is now as high as 9:1 as opposed to the recommended 2:1. The enormous amount of carcass fat is a consequence of intensive production methods with a focus on fast body weight gain. Feed is high-energy, grain-based feed rich in omega-6 fats and almost devoid of omega-3 as opposed to a natural diet they would obtain from grazing and foraging in the pasture.

Animals are fed growth promoters and raised intensively in barns or stalls with no opportunity to exercise and so fat infiltrates their wasted muscles. The transformation of chicken is an outstanding example because since the 1970’s there has been a 9 fold increase in the fat/protein ratio. The current omega-3 content of a chicken has fallen by 85% to levels that are beyond negligible in nutritional terms.
(see Modern organic and broiler chickens sold for human consumption provide more energy from fat than protein. Wang Y, Lehane C, Ghebremeskel K, Crawford MA. Public Health Nutr. 2010 Mar;13(3):400-8.)

Often it is children who are the most vulnerable.

The World Health Organization (WHO, 2002) predicted a 50% increase in child mental-ill health by 2020 and also confirmed that the rise in obesity and diabetes was due to an increase in sedentary lifestyle, in addition to an excessive consumption of energy-dense refined foods rich in salt, sugar, and saturated fats.This has led to a new type of malnutrition called Type B which is the result of multiple micronutrient depletion and the globalization of the Western food systems.

The fact is foods can mediate brain function and its signals to positively influence synaptic transmission and plasticity, membrane fluidity and energy metabolism.

Depending on the types of daily foods eaten, the results can be polar opposites. Foods can either give rise to health promoting effects resulting in positive affective states, more efficient cell-signaling and overall well-being or contrastingly promote inflammation, stress and foster addictions giving rise to negative behavioral states such as aggression, pain, anxiety and depression.
There are at least 39 essential nutrients which must be provided by our food and some of these are thought to facilitate brain function at a molecular level: